On June 1, 2015, new rules take effect for the classification
and labeling ("C&L") of hazardous chemicals and
mixtures distributed in the European Union ("EU").
The new standards were established in the EU's Classification,
Labeling, and Packaging Regulation 1272/2008 ("CLP"), and
they are binding upon all manufacturers, importers, or downstream
users ("operators") bringing hazardous mixtures to
market.
Also on June 1, 2015, a transitional period, during which
operators could choose between applying either the CLP or the
previous Dangerous Preparations Directive 1999/45
("DPD"), will come to the end. In addition and on the
same date, a sell-off "grandfathering period" for
mixtures with the DPD C&L already in the supply chain will
commence and then run until June 2017.
Among other changes, the CLP:
- Introduces different classification thresholds in certain hazard categories, such as acute toxicity and eye/skin irritation, which may result in classification to a more severe hazard category than under the DPD.
- Implements new classesfor physical hazards, which are in line with the United Nations's Globally Harmonized System of Classification and Labeling ("GHS"), as well as multiplying "M-factors" for mixtures containing substances classified as hazardous to the aquatic environment.
- Sets more stringent thresholds for the use of precautionary statements for mixtures containing sensitizing substances.
- Introduces new hazard pictograms, which are in line with the GHS and which should replace DPD pictograms.
New Tools for Classifying Mixtures
Notably, the CLP introduces, in line with the GHS, two new tools
for the classification of mixtures—the "bridging
principles" and "weight of evidence."
These tools either replace or are to be used in conjunction with
calculation methods using default-concentration thresholds of the
ingredient substances. In essence, these tools may prevent the
application of more severe classifications to the chemicals or
mixtures in question.
The new tools are designed to use available data on similar
mixtures (bridging principles), and/or read-across and other
alternative data sources, using expert judgment (weight of
evidence).
Similar to the DPD, Article 6(1) CLP provides that for the
classification of a mixture, operators should primarily take into
consideration the relevant available data on the mixture itself.
Going beyond the DPD, however, Article 9(3) CLP explicitly allows
the use of expert judgment and the weight of evidence approach
where classification criteria cannot be applied directly to the
available data.
In another new feature, Article 6(5) CLP (in connection with
Article 9(4) CLP) provides that where data are not available on the
mixture itself, other available information on similar-tested
mixtures should be used, using so-called bridging principles
(Section 1.1.3. to Annex I CLP).
Only in cases where data on the mixture itself—or on similar
mixtures—are not available, taking into consideration the
weight of evidence assessment, should the operators use calculation
methods on the basis of hazardous substances contained in the
mixture, using respective default concentration thresholds (see
Article 6(5) in connection to Article 9(4) second paragraph).
Thus, the decision tree is as follows:
- Use testing data available on the mixture as a whole (using the weight of evidence, if appropriate). If such data is not available or only partially available, then:
- Use testing data on similar mixtures, applying bridging principles. If still impossible to classify, then:
- Use calculation methods based on the hazard of known ingredients and the use of default concentration thresholds.
(See similar sequence in Section 1.6.3. and under Figure
1.6.1–a of the European Chemicals Agency ("ECHA")
Guidance on the Application of the CLP Criteria.
Note: The precedence of bridging principles over
calculation methods, however, is not applicable to carcinogenic,
mutagenic, and reproductive toxicity endpoints. For those
endpoints, data on the mixture itself or on similar mixtures can be
used only upon demonstration that the calculation methods based on
the hazard of known ingredients are not conclusive.
Scope of the Bridging Principles
Application of the bridging principles is set out in Section
1.1.3. of Annex I to CLP, which provides, "where the mixture
itself has not been tested to determine its hazardous properties,
but there are sufficient data on similar tested mixtures and
individual hazardous ingredient substances to adequately
characterize the hazards of the mixture, these data shall be used
(...)."
As follows from detailed rules in Section 1.1.3., the bridging
principles are in fact applicable only if the target mixture and
the original tested mixture are substantially similar with respect
to their hazardous ingredient substances, i.e., if they
contain ingredient substances in the same hazard category and
within the same concentrations, or within permitted concentration
variations as set out in Table 1.2. For example, Section 1.1.3.1.
sets out that even if the target mixture is diluted with a
nonhazardous diluting agent, it should still have the same
classification as the (nondiluted) original mixture. It is clear
that in this case, operators would rather use the calculation
methods, in order to take into consideration lower concentrations
in the target mixture.
These considerations limit the usability of the bridging
principles. The ECHA confirms, "the bridging principles mainly
apply to either very simple mixtures or very straightforward
compositional changes in an already classified mixture."
The CLP encourages networks of operators to facilitate the
exchange of data and application of the bridging principles. Thus,
operators seeking to explore opportunities to apply the bridging
principles should contact relevant industry associations, e.g.,
Registration, Evaluation, Authorization, and Restriction of
Chemicals ("REACH") consortia, etc.
Conditions for the Use of Weight of Evidence
The CLP provides that weight of evidence principles should be
used where classification criteria cannot be directly applied to
available identified information, "in order to ensure that
existing information can be used for as many mixtures as
possible."
The weight of evidence includes grouping and read-across
techniques, whereby endpoint information from one chemical is used
to predict the same endpoint for another chemical considered to be
similar. These techniques are similar to the bridging principles,
but they can also be used where information is insufficient for the
applicability of the bridging principles.
Similar to the classification of substances, the weight of
evidence for mixtures also includes other elements, such as results
of suitable in vitro tests, relevant animal data, (Quantitative)
Structure-Activity Relationships ("(Q)SAR") results,
human experience such as occupational data and accident databases,
epidemiological and clinical studies, and well-documented case
reports and observations. All available information bearing on the
determination of a hazard should be considered together. Expert
judgment is needed in a total weight of evidence approach.
Further information on the weight of evidence determination is
provided in the ECHA Guidance on information requirements and
chemical safety assessment.
Conclusion
The CLP's C&L rules for mixtures, which will become
binding as of June 1, 2015, notably introduce greater flexibility
for operators via the "bridging principles" and the
"weight of evidence" approaches. Such methodology can be
used instead of calculation methods using default-concentration
thresholds of the ingredient substances.
The bridging principles use the testing data on similar mixtures
for the classification of the target mixture. However, the actual
applicability of such principles is rather limited. In fact, the
bridging principles are applicable only if the target mixture and
the original tested mixture are substantially similar with respect
to their hazardous ingredient substances, i.e., if they contain
ingredient substances in the same hazard category and within the
same concentrations (or within permitted concentration
variations).
The applicability of the weight of evidence approach may be
broader, as it allows the use of additional alternative data. If
such data, when considered together with expert judgment, suggest a
classification of the mixture, the applicability of calculation
methods might be avoided.
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